You may need to try the long way around. Using the Developer tools -> Network screen, click on the "Preserve Log upon Navagation" icon. Run the extension and see what interactions the extension has with the servers. Copy these in to your Perl editor and see if you can replicate the results using LWP or one of the WWW::Mechanize modules...
Thank you very much for your replies! both sound very promising. I think I will start with trying to run the add on from Perl and if that does not work, I will move to Firefox.
Thanks